There is confusion over the exact grounds for Israeli opposition leader Tzipi Livni cancelling a trip to Britain.

Ms Livni, who had been due to speak at Sunday’s JNF Vision 2010 conference in Hendon, north-west London, said through her office that she had cancelled the trip a fortnight ago for scheduling reasons.

It had been thought she would meet Prime Minister Gordon Brown, and possibly Foreign Secretary David Miliband, for private talks.

The JNF said on Monday that it “regretted” the fact Ms Livni had not attended the conference, but chair Samuel Hayek could not confirm the reasons for the cancellation. He said it was also regrettable that “the British Government is unable to conduct free dialogue with Israel’s most senior statesmen and politicians”, but did not expand further.

It is not known when exactly the JNF was made aware that Ms Livni would not be attending. On Friday afternoon staff were still indicating she would travel to London.

Despite claims in Arab-language media, it has not been possible to establish whether an arrest warrant was sought, or issued, with Scotland Yard declining to comment on the matter.

Speaking at the conference, Israeli Ambassador Ron Prosor had referred to “the problem of universal jurisdiction”, the legal loophole which allows individuals in Britain to seek the arrest of former IDF officers on charges of alleged war crimes.